RFCs Supported by Cyrus IMAP¶
The following is an inventory of RFCs supported by Cyrus IMAP.
Standard for the format of ARPA Internet text messages, obsoleted by RFC 2822.
Network News Transfer Protocol
Standard for interchange of USENET messages
Interactive Mail Access Protocol: Version 2
Representation of Non-ASCII Text in Internet Message Headers
SMTP Service Extension for 8bit-MIMEtransport
SMTP Service Extensions
SMTP Service Extension for Message Size Declaration
Post Office Protocol - Version 3 (POP3)
DEFLATE Compressed Data Format Specification version 1.3
GZIP file format specification version 4.3
Local Mail Transfer Protocol
SMTP Service Extension for Returning Enhanced Error Codes
Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies
Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types
MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for Non-ASCII Text
Internet Message Access Protocol - Version 4rev1, obsoleted by RFC 3501.
IMAP4 ACL Extension, obsoleted by RFC 4314.
Note
Backwards compatibility with this RFC is to be obsoleted.
IMAP4 QUOTA extension, obsoleted by RFC 9208.
IMAP4 non-synchronizing literals, obsoleted by RFC 7888.
IMAP4 IDLE command
IMAP URL Scheme, obsoleted by RFC 5092.
IMAP4 Mailbox Referrals
IMAP/POP AUTHorize Extension for Simple Challenge/Response
The TLS Protocol Version 1.0
Extensible Message Format for Message Disposition Notifications (MDNs)
IMAP4 Namespace
IMAP4 UIDPLUS extension, obsoleted by RFC 4315
A MIME Content-Type for Directory Information
vCard MIME Directory Profile
The One-Time-Password SASL Mechanism
POP3 Extension Mechanism
HTTP Extensions for Distributed Authoring -- WEBDAV
Using TLS with IMAP, POP3 and ACAP
HTTP Upgrading to TLS Within HTTP/1.1
HTTP Over TLS
Simple Mail Transfer Protocol
Internet Message Format
Using Digest Authentication as a SASL Mechanism
SMTP Service Extension for Command Pipelining
IMAP4 ID extension
Common NNTP Extensions
Sieve: A Mail Filtering Language
The SYS and AUTH POP Response Codes
SMTP Service Extension for Secure SMTP over TLS
Versioning Extensions to WebDAV (Web Distributed Authoring and Versioning)
Date and Time on the Internet: Timestamps
IMAP4 Child Mailbox Extension
Sieve Extension: Relational Tests
Enhanced Mail System Status Codes
Internet Message Access Protocol - version 4rev1, obsoleted by RFC 9051.
IMAP MULTIAPPEND extension
IMAP4 Binary Content Extension
Sieve Email Filtering -- Subaddress Extension, obsoleted by RFC 5233.
MUPDATE Protocol (For Cyrus Murder)
Internet Message Access Protocol (IMAP) UNSELECT command
Web Distributed Authoring and Versioning (WebDAV) Access Control Protocol
Recommendations for Automatic Responses to Electronic Mail
ESMTP and LMTP Transmission Types Registration
Sieve Extension: Copying Without Side Effects
Network News Transfer Protocol (NNTP)
The Atom Syndication Format
IMAP4 Access Control List (ACL) Extension
Internet Message Access Protocol (IMAP) - UIDPLUS extension
Quota and Size Properties for Distributed Authoring and Versioning (DAV) Collections
The Transport Layer Security (TLS) Protocol Version 1.1
Simple Authentication and Security Layer (SASL)
Collected Extensions to IMAP4 ABNF
Internet Message Access Protocol (IMAP) - URLAUTH Extension, updated by RFC 5092.
Internet Message Access Protocol (IMAP) CATENATE Extension
Anonymous Simple Authentication and Security Layer (SASL) Mechanism
Internet Email to Support Diverse Service Environments (Lemonade) Profile
IMAP Extension for Conditional STORE Operation or Quick Flag Changes Resynchronization, obsoleted by RFC 7162.
SPNEGO-based Kerberos and NTLM HTTP Authentication in Microsoft Windows
The PLAIN Simple Authentication and Security Layer (SASL) Mechanism
Using Transport Layer Security (TLS) with Network News Transfer Protocol (NNTP)
Network News Transfer Protocol (NNTP) Extension for Authentication
Network News Transfer Protocol (NNTP) Extension for Streaming Feeds
IMAP4 Extension to SEARCH Command for Controlling What Kind of Information Is Returned
Calendaring Extensions to WebDAV (CalDAV)
HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV)
SMTP Service Extension for Authentication
IMAP Extension for Simple Authentication and Security Layer (SASL) Initial Client Response
The IMAP COMPRESS Extension
WITHIN Search Extension to the IMAP Protocol
The Post Office Protocol (POP3) Simple Authentication and Security Layer (SASL) Authentication Mechanism
IMAP URL Scheme, updated by RFC 5593.
The IMAP ENABLE Extension
IMAP4 Extensions for Quick Mailbox Resynchronization, obsoleted by RFC 7162.
Sieve Email Filtering: Body Extension
IMAP Extension for Referencing the Last SEARCH Result
Sieve Email Filtering: Environment Extension
Sieve: A Mail Filtering Language
Sieve Email Filtering: Variables Extension
Sieve Email Filtering: Vacation Extension
Sieve Email Filtering: Relational Extension
Sieve Email Filtering: Imap4flags Extension
New in version 2.5.0.
Sieve Email Filtering: Subaddress Extension
Sieve Email Filtering: Spamtest and Virustest Extensions
Internet Message Access Protocol - SORT and THREAD Extensions
Internet Message Access Protocol - ANNOTATE Extension
Internet Message Access Protocol version 4 - LIST Command Extensions
Sieve Email Filtering: Date and Index Extensions
New in version 2.5.0.
Contexts for IMAP4
Note
The ESORT capability is implemented. The CONTEXT=SEARCH and CONTEXT=SORT capabilities are not implemented.
Sieve Email Filtering: Editheader Extension
Simple Mail Transfer Protocol
Internet Message Format
Note
The JMAP mapping is incomplete.
WebDAV Current Principal Extension
Internet Message Store Events
Sieve Email Filtering: Reject and Extended Reject Extensions
Sieve Email Filtering: Extension for Notifications
Sieve Notification Mechanism: mailto
Sieve Email Filtering: Ihave Extension
The IMAP METADATA Extension
The IMAP NOTIFY Extension
The Sieve Mail-Filtering Language -- Extensions for Checking Mailbox Status and Accessing Mailbox Metadata
Extended URLFETCH for Binary and Converted Parts
Netnews Article Format
Netnews Architecture and Protocols
Internet Calendaring and Scheduling Core Object Specification (iCalendar)
iCalendar Transport-Independent Interoperability Protocol (iTIP)
The Internet Email to Support Diverse Service Environments (Lemonade) Profile
Note
The URL-PARTIAL capability is implemented. The CONTEXT=SEARCH, CONTEXT=SORT, CONVERT, I18NLEVEL=1, and NOTIFY capabilities are not implemented.
Internet Message Access Protocol (IMAP) - URL Access Identifier Extension
Extended MKCOL for Web Distributed Authoring and Versioning (WebDAV)
Sieve Email Filtering: MIME Part Tests, Iteration, Extraction, Replacement, and Enclosure
A protocol for Remotely Managing Sieve Scripts
IMAP4 Extension for Returning STATUS Information in Extended LIST
Display-Based Address Sorting for the IMAP4 SORT Extension
Using POST to Add Members to Web Distributed Authoring and Versioning (WebDAV) Collections
Sieve Email Filtering: Delivery Status Notifications and Deliver-By Extensions
iCalendar Message-Based Interoperability Protocol (iMIP)
The Secure Sockets Layer (SSL) Protocol Version 3.0
Note
SSLv3 is considered insecure as it is vulnerable to POODLE.
Support for SSLv3 is being deprecated and removed.
Sieve Vacation Extension: "Seconds" Parameter
Sieve Extension: Externally Stored Lists
IMAP LIST Extension for Special-Use Mailboxes
Note
The LIST and LSUB commands return the special-use flags, unless the
specialusealwaysconfiguration variable is explicitly turned off.
IMAP4 Extension for Fuzzy Search
xCal: The XML Format for iCalendar
vCard Format Specification
CardDAV: vCard Extensions to Web Distributed Authoring and Versioning (WebDAV)
DomainKeys Identified Mail (DKIM) Signatures
Sieve Extension for Converting Messages before Delivery
The WebSocket Protocol
Collection Synchronization for Web Distributed Authoring and Versioning (WebDAV)
Additional HTTP Status Codes
Sieve Email Filtering: Include Extension
Scheduling Extensions to CalDAV
Locating Services for Calendaring Extensions to WebDAV (CalDAV) and vCard Extensions to WebDAV (CardDAV)
HTTP Strict Transport Security (HSTS)
Internet Message Access Protocol (IMAP) - MOVE Extension
New in version 2.5.0.
JavaScript Object Notation (JSON) Pointer
IMAP Extensions: Quick Flag Changes Resynchronization (CONDSTORE) and Quick Mailbox Resynchronization (QRESYNC)
Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing
Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content
Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests
Hypertext Transfer Protocol (HTTP/1.1): Range Requests
Hypertext Transfer Protocol (HTTP/1.1): Caching
Hypertext Transfer Protocol (HTTP/1.1): Authentication
The Hypertext Transfer Protocol Status Code 308 (Permanent Redirect)
Forwarded HTTP Extension
Prefer Header for HTTP
jCal: The JSON Format for iCalendar
Sieve Email Filtering: Detecting Duplicate Deliveries
IMAP4 Multimailbox SEARCH Extension
Non-Gregorian Recurrence Rules in the Internet Calendaring and Scheduling Core Object Specification (iCalendar)
Hypertext Transfer Protocol Version 2 (HTTP/2)
HTTP Authentication-Info and Proxy-Authentication-Info Response Header Fields
HTTP Digest Access Authentication
The 'Basic' HTTP Authentication Scheme
Compression Extensions for WebSocket
Hypertext Transfer Protocol (HTTP) Client-Initiated Content-Encoding
An HTTP Status Code to Report Legal Obstacles
Salted Challenge Response HTTP Authentication Mechanism
Time Zone Data Distribution Service
CalDAV: Time Zones by Reference
IMAP4 Non-synchronizing Literals
The IMAP APPENDLIMIT Extension
Brotli Compressed Data Format
Calendar Availability
New Properties for iCalendar
Note
Support here means, that when the iCalendar stream is retrieved with HTTP GET, Cyrus IMAP inserts the color, description and name from the WebDAV properties. IMAGE, SOURCE, multi-lingual calendar DESCRIPTIONs, URL, LAST-MODIFIED, CATEGORIES, and REFRESH-INTERVAL are not exported on iCalendar streams retrieved with GET.
Individual iCalendar objects (VEVENT, VTODO, VJOURNAL) can be uploaded and downloaded with the New Properties for iCalendar.
Use of the Prefer Header Field in Web Distributed Authoring and Versioning (WebDAV)
HTTP Immutable Responses
Web Linking
An HTTP Status Code for Indicating Hints
IMAP UNAUTHENTICATE Extension for Connection Reuse
IMAP Extension for STATUS=SIZE
IMAP4 Extension for Returning MYRIGHTS Information in Extended LIST
Bootstrapping WebSockets with HTTP/2
IMAP Extension for Object Identifiers
IMAP REPLACE Extension
Internet Message Access Protocol (IMAP) - SAVEDATE Extension
Sieve Email Filtering: Delivering to Special-Use Mailboxes
Sieve Extension: File Carbon Copy (FCC)
Calendaring Extensions to WebDAV (CalDAV): Managed Attachments
The JSON Meta Application Protocol (JMAP)
The JSON Meta Application Protocol (JMAP) for Mail
Zstandard Compression and the application/zstd Media Type
A JSON Meta Application Protocol (JMAP) Subprotocol for WebSocket
IMAP4 Extension: Message Preview Generation
Internet Message Access Protocol (IMAP) - version 4rev2
IMAP QUOTA Extension
IETF RFC Drafts¶
draft-ietf-extra-imap-list-metadata
IMAP4 Extension for Returning Mailbox METADATA in Extended LIST
draft-ietf-extra-sieve-mailboxid
Sieve Email Filtering: delivery by mailboxid
draft-ietf-extra-sieve-snooze
Sieve Email Filtering: Snooze Extension
draft-ietf-extra-imap-uidonly
IMAP Extension for only using and returning UIDs
draft-ietf-jmap-calendars
JMAP for Calendars
draft-ietf-jmap-sieve
JMAP for Sieve Scripts
draft-murchison-lmtp-ignorequota
LMTP Service Extension for Ignoring Recipient Quotas
[MS-NTHT] NTLM Over HTTP Protocol Specification
draft-ietf-sieve-regex
Sieve Email Filtering -- Regular Expression Extension
draft-york-vpoll
VPOLL: Consensus Scheduling Component for iCalendar
draft-desruisseaux-ischedule
Internet Calendar Scheduling Protocol (iSchedule)
draft-thomson-hybi-http-timeout
Hypertext Transfer Protocol (HTTP) Keep-Alive Header
caldav-ctag Calendar Collection Entity Tag (CTag) in CalDAV Brief Header Microsoft 'Brief' header extension
RFC Wishlist¶
IMAP4 Login Referrals
Transparent Content Negotiation in HTTP
The Use of URLs as Meta-Syntax for Core Mail List Commands and their Transport through Message Header Fields
Delta encoding in HTTP
Internet Message Access Protocol Internationalization
Internet Message Access Protocol - CONVERT Extension
Sieve Notification Mechanism: Extensible Messaging and Presence Protocol (XMPP)
IMAP4 Extension for Named Searches (Filters)
Binding Extensions to Web Distributed Authoring and Versioning (WebDAV)
Sieve Notification Mechanism: SIP MESSAGE
Support for Internet Message Access Protocol (IMAP) Events in Sieve
IMAP Support for UTF-8
Using Early Data in HTTP